Bildercache für den Webserver nginx am Beispiel von Gravatar-Icons

server {
    listen                                  80;
    server_name                             img.yourdomain.tld;
    error_log                               /path/to/your/logs/error/img.yourdomain.tld.log warn;
    root                                    /path/to/your/document/root/;
 
    location ~ \.php$ {
        fastcgi_pass            127.0.0.1:1234;
        include                 /etc/nginx/fastcgi_params;
    }
 
    location / {
        index                           cdn.php;
        # if the requested file exists, return it immediately
        if (-f $request_filename) {
            break;
        }
 
        # all other requests go to CDN-PHP-File
        if (!-e $request_filename) {
            rewrite ^(.+)$ /cdn.php last;
        }
    }
}

<?php
// Script by Uli Wolf - https://wolf-u.li
 
<?php
$url=explode("/", $_SERVER['REQUEST_URI']);
 
// Type
$url[1] = strtolower(preg_replace("/[^a-zA-Z\s]/", "", $url[1]));
 
// Now evaluate the type
if(strlen($url[1])==1) {
        switch($url[1]) {
                case "g":
                        cache_get_gravatar($url);
                break;
                default:
                        exit;
                break;
        }
}
 
 
function cache_get_gravatar($url) {
        $cache['type']=$url[1];
        $cache['size']=$url[2];
        $cache['hash']=$url[3];
        if(!is_dir("./g")) { mkdir("./g"); }
        // Size
        $cache['size'] = preg_replace("/[^0-9\s]/", "", $cache['size']);
        if(!is_dir("./g/" . $cache['size'])) { mkdir("./g/" . $cache['size']); }
 
        // Key
        // - The String looks like: 3c7257f1a8c44frc6oae3ed84cd78a88.png
        $cache['hash'] = explode(".", $cache['hash']);
        // - The String looks like: 3c7257f1a8c44frc6oae3ed84cd78a88
        $cache['hash'] = preg_replace("/[^a-zA-Z0-9\s]/", "", $cache['hash'][0]);
        // Check correct string length
        if(strlen($cache['hash'])!=32) {exit;}
 
        // If the mailadress was not found, you can get various images:
        // - identicon
        // - monsterid
        // - wavatar
        // - mm (mysteryman)
        $mailnotfound = "mm";
        $grav_img = "http://www.gravatar.com/avatar/" . $cache['hash'] . "?s=" . $cache['size'] . "&d=" . $mailnotfound . "&r=G";
        if(extension_loaded('curl')) {
                $gch = curl_init();
                $gcurl_options = array(
                        CURLOPT_URL => $grav_img,
                        CURLOPT_HEADER => false,
                        CURLOPT_RETURNTRANSFER => true,
                        CURLOPT_TIMEOUT => 20,
                        CURLOPT_BINARYTRANSFER => true,
                        CURLOPT_MAXREDIRS => 2
                );
                curl_setopt_array($gch, $gcurl_options);
 
                $gdata = curl_exec($gch);
                if(!curl_errno($gch)) {
                        $info = curl_getinfo($ch);
                        if(curl_getinfo($gch, CURLINFO_HTTP_CODE) != 200) {
                                echo "Foo";
                                exit;
                        }
                }
                curl_close ($gch);
                unset($gch);
        }
        $gfilehandle_img = fopen("g/" . $cache['size'] . "/"  . $cache['hash'] . ".png", "wb+");
        fwrite($gfilehandle_img, $gdata);
        fclose($gfilehandle_img);
        unset($gfilehandle_img);
 
        header('content-type: image/png');
        echo $gdata;
}